/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
 */
#ifndef __LINUX_BIO_H
#define __LINUX_BIO_H

#include <linux/highmem.h>
#include <linux/mempool.h>
#include <linux/ioprio.h>
/* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
#include <linux/blk_types.h>

#define BIO_DEBUG

#ifdef BIO_DEBUG
#define BIO_BUG_ON      BUG_ON
#else
#define BIO_BUG_ON
#endif

#define BIO_MAX_PAGES           256

#define bio_prio(bio)                   (bio)->bi_ioprio
#define bio_set_prio(bio, prio)         ((bio)->bi_ioprio = prio)

#define bio_iter_iovec(bio, iter)                               \
        bvec_iter_bvec((bio)->bi_io_vec, (iter))

#define bio_iter_page(bio, iter)                                \
        bvec_iter_page((bio)->bi_io_vec, (iter))
#define bio_iter_len(bio, iter)                                 \
        bvec_iter_len((bio)->bi_io_vec, (iter))
#define bio_iter_offset(bio, iter)                              \
        bvec_iter_offset((bio)->bi_io_vec, (iter))

#define bio_page(bio)           bio_iter_page((bio), (bio)->bi_iter)
#define bio_offset(bio)         bio_iter_offset((bio), (bio)->bi_iter)
#define bio_iovec(bio)          bio_iter_iovec((bio), (bio)->bi_iter)

#define bio_multiple_segments(bio)                              \
        ((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)

#define bvec_iter_sectors(iter) ((iter).bi_size >> 9)
#define bvec_iter_end_sector(iter) ((iter).bi_sector + bvec_iter_sectors((iter)))

#define bio_sectors(bio)        bvec_iter_sectors((bio)->bi_iter)
#define bio_end_sector(bio)     bvec_iter_end_sector((bio)->bi_iter)

/*
 * Return the data direction, READ or WRITE.
 */
#define bio_data_dir(bio) \
        (op_is_write(bio_op(bio)) ? WRITE : READ)

/*
 * Check whether this bio carries any data or not. A NULL bio is allowed.
 */
static inline bool bio_has_data(struct bio *bio)
{
        if (bio &&
            bio->bi_iter.bi_size &&
            bio_op(bio) != REQ_OP_DISCARD &&
            bio_op(bio) != REQ_OP_SECURE_ERASE &&
            bio_op(bio) != REQ_OP_WRITE_ZEROES)
                return true;

        return false;
}

static inline bool bio_no_advance_iter(const struct bio *bio)
{
        return bio_op(bio) == REQ_OP_DISCARD ||
               bio_op(bio) == REQ_OP_SECURE_ERASE ||
               bio_op(bio) == REQ_OP_WRITE_SAME ||
               bio_op(bio) == REQ_OP_WRITE_ZEROES;
}

static inline bool bio_mergeable(struct bio *bio)
{
        if (bio->bi_opf & REQ_NOMERGE_FLAGS)
                return false;

        return true;
}

static inline unsigned int bio_cur_bytes(struct bio *bio)
{
        if (bio_has_data(bio))
                return bio_iovec(bio).bv_len;
        else /* dataless requests such as discard */
                return bio->bi_iter.bi_size;
}

static inline void *bio_data(struct bio *bio)
{
        if (bio_has_data(bio))
                return page_address(bio_page(bio)) + bio_offset(bio);

        return NULL;
}

/**
 * bio_full - check if the bio is full
 * @bio:        bio to check
 * @len:        length of one segment to be added
 *
 * Return true if @bio is full and one segment with @len bytes can't be
 * added to the bio, otherwise return false
 */
static inline bool bio_full(struct bio *bio, unsigned len)
{
        if (bio->bi_vcnt >= bio->bi_max_vecs)
                return true;

        if (bio->bi_iter.bi_size > UINT_MAX - len)
                return true;

        return false;
}

static inline bool bio_next_segment(const struct bio *bio,
                                    struct bvec_iter_all *iter)
{
        if (iter->idx >= bio->bi_vcnt)
                return false;

        bvec_advance(&bio->bi_io_vec[iter->idx], iter);
        return true;
}

/*
 * drivers should _never_ use the all version - the bio may have been split
 * before it got to the driver and the driver won't own all of it
 */
#define bio_for_each_segment_all(bvl, bio, iter) \
        for (bvl = bvec_init_iter_all(&iter); bio_next_segment((bio), &iter); )

static inline void bio_advance_iter(const struct bio *bio,
                                    struct bvec_iter *iter, unsigned int bytes)
{
        iter->bi_sector += bytes >> 9;

        if (bio_no_advance_iter(bio))
                iter->bi_size -= bytes;
        else
                bvec_iter_advance(bio->bi_io_vec, iter, bytes);
                /* TODO: It is reasonable to complete bio with error here. */
}

/* @bytes should be less or equal to bvec[i->bi_idx].bv_len */
static inline void bio_advance_iter_single(const struct bio *bio,
                                           struct bvec_iter *iter,
                                           unsigned int bytes)
{
        iter->bi_sector += bytes >> 9;

        if (bio_no_advance_iter(bio))
                iter->bi_size -= bytes;
        else
                bvec_iter_advance_single(bio->bi_io_vec, iter, bytes);
}

#define __bio_for_each_segment(bvl, bio, iter, start)                   \
        for (iter = (start);                                            \
             (iter).bi_size &&                                          \
                ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
             bio_advance_iter_single((bio), &(iter), (bvl).bv_len))

#define bio_for_each_segment(bvl, bio, iter)                            \
        __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)

#define __bio_for_each_bvec(bvl, bio, iter, start)              \
        for (iter = (start);                                            \
             (iter).bi_size &&                                          \
                ((bvl = mp_bvec_iter_bvec((bio)->bi_io_vec, (iter))), 1); \
             bio_advance_iter_single((bio), &(iter), (bvl).bv_len))

/* iterate over multi-page bvec */
#define bio_for_each_bvec(bvl, bio, iter)                       \
        __bio_for_each_bvec(bvl, bio, iter, (bio)->bi_iter)

/*
 * Iterate over all multi-page bvecs. Drivers shouldn't use this version for the
 * same reasons as bio_for_each_segment_all().
 */
#define bio_for_each_bvec_all(bvl, bio, i)              \
        for (i = 0, bvl = bio_first_bvec_all(bio);      \
             i < (bio)->bi_vcnt; i++, bvl++)            \

#define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)

static inline unsigned bio_segments(struct bio *bio)
{
        unsigned segs = 0;
        struct bio_vec bv;
        struct bvec_iter iter;

        /*
         * We special case discard/write same/write zeroes, because they
         * interpret bi_size differently:
         */

        switch (bio_op(bio)) {
        case REQ_OP_DISCARD:
        case REQ_OP_SECURE_ERASE:
        case REQ_OP_WRITE_ZEROES:
                return 0;
        case REQ_OP_WRITE_SAME:
                return 1;
        default:
                break;
        }

        bio_for_each_segment(bv, bio, iter)
                segs++;

        return segs;
}

/*
 * get a reference to a bio, so it won't disappear. the intended use is
 * something like:
 *
 * bio_get(bio);
 * submit_bio(rw, bio);
 * if (bio->bi_flags ...)
 *      do_something
 * bio_put(bio);
 *
 * without the bio_get(), it could potentially complete I/O before submit_bio
 * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 * runs
 */
static inline void bio_get(struct bio *bio)
{
        bio->bi_flags |= (1 << BIO_REFFED);
        smp_mb__before_atomic();
        atomic_inc(&bio->__bi_cnt);
}

static inline void bio_cnt_set(struct bio *bio, unsigned int count)
{
        if (count != 1) {
                bio->bi_flags |= (1 << BIO_REFFED);
                smp_mb();
        }
        atomic_set(&bio->__bi_cnt, count);
}

static inline bool bio_flagged(struct bio *bio, unsigned int bit)
{
        return (bio->bi_flags & (1U << bit)) != 0;
}

static inline void bio_set_flag(struct bio *bio, unsigned int bit)
{
        bio->bi_flags |= (1U << bit);
}

static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
{
        bio->bi_flags &= ~(1U << bit);
}

static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
{
        *bv = bio_iovec(bio);
}

static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
{
        struct bvec_iter iter = bio->bi_iter;
        int idx;

        if (unlikely(!bio_multiple_segments(bio))) {
                *bv = bio_iovec(bio);
                return;
        }

        bio_advance_iter(bio, &iter, iter.bi_size);

        if (!iter.bi_bvec_done)
                idx = iter.bi_idx - 1;
        else    /* in the middle of bvec */
                idx = iter.bi_idx;

        *bv = bio->bi_io_vec[idx];

        /*
         * iter.bi_bvec_done records actual length of the last bvec
         * if this bio ends in the middle of one io vector
         */
        if (iter.bi_bvec_done)
                bv->bv_len = iter.bi_bvec_done;
}

static inline struct bio_vec *bio_first_bvec_all(struct bio *bio)
{
        WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
        return bio->bi_io_vec;
}

static inline struct page *bio_first_page_all(struct bio *bio)
{
        return bio_first_bvec_all(bio)->bv_page;
}

static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
{
        WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
        return &bio->bi_io_vec[bio->bi_vcnt - 1];
}

enum bip_flags {
        BIP_BLOCK_INTEGRITY     = 1 << 0, /* block layer owns integrity data */
        BIP_MAPPED_INTEGRITY    = 1 << 1, /* ref tag has been remapped */
        BIP_CTRL_NOCHECK        = 1 << 2, /* disable HBA integrity checking */
        BIP_DISK_NOCHECK        = 1 << 3, /* disable disk integrity checking */
        BIP_IP_CHECKSUM         = 1 << 4, /* IP checksum */
};

/*
 * bio integrity payload
 */
struct bio_integrity_payload {
        struct bio              *bip_bio;       /* parent bio */

        struct bvec_iter        bip_iter;

        unsigned short          bip_slab;       /* slab the bip came from */
        unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
        unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
        unsigned short          bip_flags;      /* control flags */

        struct bvec_iter        bio_iter;       /* for rewinding parent bio */

        struct work_struct      bip_work;       /* I/O completion */

        struct bio_vec          *bip_vec;
        struct bio_vec          bip_inline_vecs[];/* embedded bvec array */
};

#if defined(CONFIG_BLK_DEV_INTEGRITY)

static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
{
        if (bio->bi_opf & REQ_INTEGRITY)
                return bio->bi_integrity;

        return NULL;
}

static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
{
        struct bio_integrity_payload *bip = bio_integrity(bio);

        if (bip)
                return bip->bip_flags & flag;

        return false;
}

static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
{
        return bip->bip_iter.bi_sector;
}

static inline void bip_set_seed(struct bio_integrity_payload *bip,
                                sector_t seed)
{
        bip->bip_iter.bi_sector = seed;
}

#endif /* CONFIG_BLK_DEV_INTEGRITY */

extern void bio_trim(struct bio *bio, int offset, int size);
extern struct bio *bio_split(struct bio *bio, int sectors,
                             gfp_t gfp, struct bio_set *bs);

/**
 * bio_next_split - get next @sectors from a bio, splitting if necessary
 * @bio:        bio to split
 * @sectors:    number of sectors to split from the front of @bio
 * @gfp:        gfp mask
 * @bs:         bio set to allocate from
 *
 * Returns a bio representing the next @sectors of @bio - if the bio is smaller
 * than @sectors, returns the original bio unchanged.
 */
static inline struct bio *bio_next_split(struct bio *bio, int sectors,
                                         gfp_t gfp, struct bio_set *bs)
{
        if (sectors >= bio_sectors(bio))
                return bio;

        return bio_split(bio, sectors, gfp, bs);
}

enum {
        BIOSET_NEED_BVECS = BIT(0),
        BIOSET_NEED_RESCUER = BIT(1),
};
extern int bioset_init(struct bio_set *, unsigned int, unsigned int, int flags);
extern void bioset_exit(struct bio_set *);
extern int biovec_init_pool(mempool_t *pool, int pool_entries);
extern int bioset_init_from_src(struct bio_set *bs, struct bio_set *src);

extern struct bio *bio_alloc_bioset(gfp_t, unsigned int, struct bio_set *);
extern void bio_put(struct bio *);

extern void __bio_clone_fast(struct bio *, struct bio *);
extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);

extern struct bio_set fs_bio_set;

static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
{
        return bio_alloc_bioset(gfp_mask, nr_iovecs, &fs_bio_set);
}

static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
{
        return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
}

extern blk_qc_t submit_bio(struct bio *);

extern void bio_endio(struct bio *);

static inline void bio_io_error(struct bio *bio)
{
        bio->bi_status = BLK_STS_IOERR;
        bio_endio(bio);
}

static inline void bio_wouldblock_error(struct bio *bio)
{
        bio_set_flag(bio, BIO_QUIET);
        bio->bi_status = BLK_STS_AGAIN;
        bio_endio(bio);
}

struct request_queue;

extern int submit_bio_wait(struct bio *bio);
extern void bio_advance(struct bio *, unsigned);

extern void bio_init(struct bio *bio, struct bio_vec *table,
                     unsigned short max_vecs);
extern void bio_uninit(struct bio *);
extern void bio_reset(struct bio *);
void bio_chain(struct bio *, struct bio *);

extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
                           unsigned int, unsigned int);
bool __bio_try_merge_page(struct bio *bio, struct page *page,
                unsigned int len, unsigned int off, bool *same_page);
void __bio_add_page(struct bio *bio, struct page *page,
                unsigned int len, unsigned int off);
int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
void bio_release_pages(struct bio *bio, bool mark_dirty);
extern void bio_set_pages_dirty(struct bio *bio);
extern void bio_check_pages_dirty(struct bio *bio);

extern void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
                               struct bio *src, struct bvec_iter *src_iter);
extern void bio_copy_data(struct bio *dst, struct bio *src);
extern void bio_list_copy_data(struct bio *dst, struct bio *src);
extern void bio_free_pages(struct bio *bio);
void zero_fill_bio_iter(struct bio *bio, struct bvec_iter iter);
void bio_truncate(struct bio *bio, unsigned new_size);
void guard_bio_eod(struct bio *bio);

static inline void zero_fill_bio(struct bio *bio)
{
        zero_fill_bio_iter(bio, bio->bi_iter);
}

extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
extern unsigned int bvec_nr_vecs(unsigned short idx);
extern const char *bio_devname(struct bio *bio, char *buffer);

#define bio_set_dev(bio, bdev)                  \
do {                                            \
        if ((bio)->bi_disk != (bdev)->bd_disk)  \
                bio_clear_flag(bio, BIO_THROTTLED);\
        (bio)->bi_disk = (bdev)->bd_disk;       \
        (bio)->bi_partno = (bdev)->bd_partno;   \
        bio_associate_blkg(bio);                \
} while (0)

#define bio_copy_dev(dst, src)                  \
do {                                            \
        (dst)->bi_disk = (src)->bi_disk;        \
        (dst)->bi_partno = (src)->bi_partno;    \
        bio_clone_blkg_association(dst, src);   \
} while (0)

#define bio_dev(bio) \
        disk_devt((bio)->bi_disk)

#ifdef CONFIG_BLK_CGROUP
void bio_associate_blkg(struct bio *bio);
void bio_associate_blkg_from_css(struct bio *bio,
                                 struct cgroup_subsys_state *css);
void bio_clone_blkg_association(struct bio *dst, struct bio *src);
#else   /* CONFIG_BLK_CGROUP */
static inline void bio_associate_blkg(struct bio *bio) { }
static inline void bio_associate_blkg_from_css(struct bio *bio,
                                               struct cgroup_subsys_state *css)
{ }
static inline void bio_clone_blkg_association(struct bio *dst,
                                              struct bio *src) { }
#endif  /* CONFIG_BLK_CGROUP */

#ifdef CONFIG_HIGHMEM
/*
 * remember never ever reenable interrupts between a bvec_kmap_irq and
 * bvec_kunmap_irq!
 */
static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
{
        unsigned long addr;

        /*
         * might not be a highmem page, but the preempt/irq count
         * balancing is a lot nicer this way
         */
        local_irq_save(*flags);
        addr = (unsigned long) kmap_atomic(bvec->bv_page);

        BUG_ON(addr & ~PAGE_MASK);

        return (char *) addr + bvec->bv_offset;
}

static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
{
        unsigned long ptr = (unsigned long) buffer & PAGE_MASK;

        kunmap_atomic((void *) ptr);
        local_irq_restore(*flags);
}

#else
static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
{
        return page_address(bvec->bv_page) + bvec->bv_offset;
}

static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
{
        *flags = 0;
}
#endif

/*
 * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 *
 * A bio_list anchors a singly-linked list of bios chained through the bi_next
 * member of the bio.  The bio_list also caches the last list member to allow
 * fast access to the tail.
 */
struct bio_list {
        struct bio *head;
        struct bio *tail;
};

static inline int bio_list_empty(const struct bio_list *bl)
{
        return bl->head == NULL;
}

static inline void bio_list_init(struct bio_list *bl)
{
        bl->head = bl->tail = NULL;
}

#define BIO_EMPTY_LIST  { NULL, NULL }

#define bio_list_for_each(bio, bl) \
        for (bio = (bl)->head; bio; bio = bio->bi_next)

static inline unsigned bio_list_size(const struct bio_list *bl)
{
        unsigned sz = 0;
        struct bio *bio;

        bio_list_for_each(bio, bl)
                sz++;

        return sz;
}

static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
{
        bio->bi_next = NULL;

        if (bl->tail)
                bl->tail->bi_next = bio;
        else
                bl->head = bio;

        bl->tail = bio;
}

static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
{
        bio->bi_next = bl->head;

        bl->head = bio;

        if (!bl->tail)
                bl->tail = bio;
}

static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
{
        if (!bl2->head)
                return;

        if (bl->tail)
                bl->tail->bi_next = bl2->head;
        else
                bl->head = bl2->head;

        bl->tail = bl2->tail;
}

static inline void bio_list_merge_head(struct bio_list *bl,
                                       struct bio_list *bl2)
{
        if (!bl2->head)
                return;

        if (bl->head)
                bl2->tail->bi_next = bl->head;
        else
                bl->tail = bl2->tail;

        bl->head = bl2->head;
}

static inline struct bio *bio_list_peek(struct bio_list *bl)
{
        return bl->head;
}

static inline struct bio *bio_list_pop(struct bio_list *bl)
{
        struct bio *bio = bl->head;

        if (bio) {
                bl->head = bl->head->bi_next;
                if (!bl->head)
                        bl->tail = NULL;

                bio->bi_next = NULL;
        }

        return bio;
}

static inline struct bio *bio_list_get(struct bio_list *bl)
{
        struct bio *bio = bl->head;

        bl->head = bl->tail = NULL;

        return bio;
}

/*
 * Increment chain count for the bio. Make sure the CHAIN flag update
 * is visible before the raised count.
 */
static inline void bio_inc_remaining(struct bio *bio)
{
        bio_set_flag(bio, BIO_CHAIN);
        smp_mb__before_atomic();
        atomic_inc(&bio->__bi_remaining);
}

/*
 * bio_set is used to allow other portions of the IO system to
 * allocate their own private memory pools for bio and iovec structures.
 * These memory pools in turn all allocate from the bio_slab
 * and the bvec_slabs[].
 */
#define BIO_POOL_SIZE 2

struct bio_set {
        struct kmem_cache *bio_slab;
        unsigned int front_pad;

        mempool_t bio_pool;
        mempool_t bvec_pool;
#if defined(CONFIG_BLK_DEV_INTEGRITY)
        mempool_t bio_integrity_pool;
        mempool_t bvec_integrity_pool;
#endif

        /*
         * Deadlock avoidance for stacking block drivers: see comments in
         * bio_alloc_bioset() for details
         */
        spinlock_t              rescue_lock;
        struct bio_list         rescue_list;
        struct work_struct      rescue_work;
        struct workqueue_struct *rescue_workqueue;
};

struct biovec_slab {
        int nr_vecs;
        char *name;
        struct kmem_cache *slab;
};

static inline bool bioset_initialized(struct bio_set *bs)
{
        return bs->bio_slab != NULL;
}

#if defined(CONFIG_BLK_DEV_INTEGRITY)

#define bip_for_each_vec(bvl, bip, iter)                                \
        for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)

#define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
        for_each_bio(_bio)                                              \
                bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)

extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
extern bool bio_integrity_prep(struct bio *);
extern void bio_integrity_advance(struct bio *, unsigned int);
extern void bio_integrity_trim(struct bio *);
extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
extern int bioset_integrity_create(struct bio_set *, int);
extern void bioset_integrity_free(struct bio_set *);
extern void bio_integrity_init(void);

#else /* CONFIG_BLK_DEV_INTEGRITY */

static inline void *bio_integrity(struct bio *bio)
{
        return NULL;
}

static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
{
        return 0;
}

static inline void bioset_integrity_free (struct bio_set *bs)
{
        return;
}

static inline bool bio_integrity_prep(struct bio *bio)
{
        return true;
}

static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
                                      gfp_t gfp_mask)
{
        return 0;
}

static inline void bio_integrity_advance(struct bio *bio,
                                         unsigned int bytes_done)
{
        return;
}

static inline void bio_integrity_trim(struct bio *bio)
{
        return;
}

static inline void bio_integrity_init(void)
{
        return;
}

static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
{
        return false;
}

static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
                                                                unsigned int nr)
{
        return ERR_PTR(-EINVAL);
}

static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
                                        unsigned int len, unsigned int offset)
{
        return 0;
}

#endif /* CONFIG_BLK_DEV_INTEGRITY */

/*
 * Mark a bio as polled. Note that for async polled IO, the caller must
 * expect -EWOULDBLOCK if we cannot allocate a request (or other resources).
 * We cannot block waiting for requests on polled IO, as those completions
 * must be found by the caller. This is different than IRQ driven IO, where
 * it's safe to wait for IO to complete.
 */
static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
{
        bio->bi_opf |= REQ_HIPRI;
        if (!is_sync_kiocb(kiocb))
                bio->bi_opf |= REQ_NOWAIT;
}

#endif /* __LINUX_BIO_H */